Report on Arctic, Antarctic research cites faster melt at both ends

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Antarctica's Pine Island Glacier is seen after deep crevasses in 2001 caused a massive iceberg to calve off. The area highlighted with a box shows other crevasses like the one that spawned the iceberg.

GENEVA — The Arctic and Antarctic regions are warming faster than previously thought, raising world sea levels and making drastic global climate change more likely than ever, international scientists said on Wednesday in summarizing a new report on recent research efforts.

The melt is particularly worrisome in West Antarctica — and not just the Antarctic Peninsula but all along the vast coastline.

"The warming we see in the peninsula also extends all the way down to what is called West Antarctica," said Colin Summerhayes, executive director of the Britain-based Scientific Committee on Antarctic Research and a member of International Polar Year's steering committee. "That's unusual and unexpected."

Summerhayes and others summarized the preliminary findings from hundreds of studies done for the International Polar Year. Scientists from more than 60 countries have been conducting intense Arctic and Antarctic research over the past two southern summer seasons — on the ice, at sea, and via icebreaker, submarine and surveillance satellite.

The preliminary IPY report stated that "it now appears certain that both the Greenland and the Antarctic ice sheets are losing mass and thus raising sea level, and that the rate of ice loss from Greenland is growing. New data also confirm that warming in the Antarctic is much more widespread than it was thought prior to IPY."

Glaciers moving fasterThe biggest West Antarctic glacier, the Pine Island Glacier, is moving 40 percent faster than it was in the 1970s, discharging water and ice more rapidly into the ocean, Summerhayes said.

The Smith Glacier, also in West Antarctica, is moving 83 percent faster than it did in 1992, he said.

All the glaciers in the area together are losing a total of around 114 billion tons per year because the discharge is much greater than the new snowfall, he said.

"That's equivalent to the current mass loss from the whole of the Greenland ice sheet," Summerhayes said, adding that the glaciers' discharge was making a significant contribution to the rise in sea levels. "We didn't realize it was moving that fast."

The glaciers are slipping into the sea faster because the floating ice shelf that would normally stop them — usually 650 to 980 feet thick — is melting.

"There's some people who fear that this is the first signs of an incipient collapse of the West Antarctic Ice Sheet," Summerhayes said.

A 2007 IPCC report predicted a sea level rise of 7 to 23 inches by the end of the century, which could flood low-lying areas and force millions to flee. The IPY group said an additional 3.9 to 7.8 inches rise was possible if the recent, surprising melting of polar ice sheets continues.